Propellor Falls Off Sydney-Bound Plane

Plane makes emergency landing.

A regional passenger plane has made an emergency landing at Sydney Airport after a propeller apparently fell off during approach.

The Regional Express flight from Albury to Sydney - carrying 16 passengers and three crew - made a distress call about midday on Friday when it was 20 kilometres from the airport.

The Saab 340 subsequently landed safely.

In the pan-pan call, the crew said the propeller assembly had "dislodged", Civil Aviation Safety Authority spokesman Peter Gibson told AAP, while photographs of the plane on the ground showed the right propeller missing altogether.

Mr Gibson said during his 20 years in the aviation industry he'd never heard of a propeller falling off a plane.

"I've never come across it ... it's very unusual," he said.

Flightradar24 suggests Rex flight 768 approached Sydney from the north meaning the propeller could have fallen into a national park, possibly Ku-ring-gai Chase.

Rex said it was investigating and would reveal more details later on Friday.

The Australian Transport Safety Bureau will conduct an independent investigation and is also due to comment further.